July 2026 (2026-07): Delivered a critical modernization effort for powsybl-diagram by upgrading the Core dependency to Core 7.3.0, aligning with the latest core library release while preserving compatibility. This upgrade reduces technical debt, improves maintainability, and unlocks access to upcoming core capabilities, positioning the project for feature work and longer-term stability. No major bugs were reported or fixed this month; the focus was on stability and forward readiness.

June 2026 monthly summary for powsybl-core: delivered three core improvements to limits handling, data management, and serialization, with comprehensive tests and documentation. Implemented loading limits detection for low limits and beta export controls with configurable options, refined validation, and default behavior; added selective import/export of active operational limits groups; introduced a name attribute for permanent limits in serialization. These changes improve data quality, export safety, and operational efficiency for IIDM models.

May 2026 monthly summary: Across powsybl-core and powsybl-diagram, delivered key features and stability fixes that improve modeling flexibility, API consistency, and visualization reliability. Enhanced LimitReduction configurability (support for values > 1) with tests and versioning updates. Implemented symmetric default connect/disconnect API across terminals, tie lines, and HVDC lines, with tests and documentation. Fixed force layout division-by-zero and added a random force utility to prevent point overlap, with comprehensive tests. These changes improve business value by enabling more expressive simulations, reducing configuration drift, and ensuring robust layouts and visualizations.

April 2026 — powsybl-core delivered focused API modernization and quality improvements. The major change was refactoring the LimitViolation API to use a LimitViolationBuilder, deprecating legacy constructors, with accompanying tests and documentation updates to enable a safe migration. This enhances readability, maintainability, and reduces the risk of misusing the API. No critical user-facing bugs were fixed this month; instead, the work minimizes future maintenance costs and supports safer downstream usage. Technologies demonstrated include Java, the builder pattern, unit testing, and Javadoc/documentation updates.

March 2026 highlights performance, reliability, and configurability improvements across powsybl-diagram and powsybl-core. Key features include Atlas2 layout enhancements with Barnes-Hut optimization and removal of the RepulsionFromFixedNodes parameter, plus adopting Atlas2ForceLayout as the default for network area diagrams with corresponding test updates. In core, granular operational limits management was expanded to support multiple active groups and selective reductions, complemented by safer connect/disconnect behavior for fictitious breakers. Additional robustness was achieved through XML serialization fixes for special characters, improved limit-violation comparisons by operationalLimitsGroupId, and preservation of selected operational limits groups during 3WT-to-1 3WT conversions. Minor RTD documentation corrections and broader test/SerDe improvements further increased reliability and maintainability.

February 2026 monthly performance summary focusing on delivering high-impact features, improving reliability, and enabling scalable visualizations across core and diagram components. Key outcomes include network stream initialization enhancements with targeted testing, comprehensive documentation improvements for usage, IIDM export/import, and error handling, and the Atlas 2 force layout implementation for graph visualization.

Month: 2026-01 — Focused on improving documentation quality for the powsybl-core repository. Key deliverables include documentation corrections for Substation Topology and VoltageLevel Javadoc, addressing inaccuracies and formatting issues to improve developer experience and API clarity.

September 2025 monthly summary for the powsybl-diagram repository focused on feature delivery, test stabilization, and quality improvements.

July 2025 monthly summary focusing on key accomplishments in powsybl-diagram. Delivered a major architectural refinement to the Force Layout, enabling modularity and easier extensibility, with a clear migration path for existing users via an adapter. This sets the groundwork for future layout strategies and improvements across the diagram module.

In May 2025, the powsybl-diagram module delivered a focused enhancement to the force-directed layout, improving diagram readability and reducing computational complexity. By removing the spring middle repulsion, diagrams render with fewer misleading edge crossings and simpler calculations, delivering clearer visuals for network diagrams. The change is captured in commit 08550551ce25030ce8f38ae9824dcfad4c0f9001 (Remove spring middle repulsion, PR #694). No major bugs were reported this month. Overall, this work enhances user comprehension, speeds up diagram rendering for typical networks, and improves the maintainability of the layout algorithm.

Month: 2025-04 | Focus: powsybl/powsybl-core. Emphasis on documentation accuracy for cross-platform build commands to improve developer experience and reduce support friction.